local new = GetRenderTarget("test_rt", 256, 256, false)

hook.Add("RenderScene", "test", function()
    local old, w, h = render.GetRenderTarget(), ScrW(), ScrH()

    render.SetRenderTarget(new)
        render.Clear(0, 0, 0, 255, false)
        render.SetViewPort(0, 0, 256, 256)
            cam.Start2D()
                draw.SimpleText("Test", "HUDNumber5", (CurTime()*100)%256, 128, color_white, TEXT_ALIGN_CENTER)
            cam.End2D()
        render.SetViewPort(0, 0, w, h)
    render.SetRenderTarget(old)
end)


local mat = CreateMaterial("test_rt_mat", "VertexLitGeneric",
    {
        ["$basetexture"] = "test_rt",
    }
)

local barrel = (function() for k,v in pairs(ents.GetAll()) do if v:GetModel() and v:GetModel():find("barrel", nil, true) then return v end end end)()

function barrel:RenderOverride()
    SetMaterialOverride(mat)
        self:DrawModel()
    SetMaterialOverride()
end